Backport class dropdown being based on current spec from PoB1

PathOfBuildingCommunity/PathOfBuilding#8494

Author: Wires77

src/Classes/TreeTab.lua

@@ -482,6 +482,7 @@ function TreeTabClass:SetActiveSpec(specId)
 	self.build.spec = curSpec
 	self.build.buildFlag = true
 	self.build.spec:SetWindowTitleWithBuildClass()
+	self.build:UpdateClassDropdowns(curSpec.treeVersion)
 	for _, slot in pairs(self.build.itemsTab.slots) do
 		if slot.nodeId then
 			if prevSpec then

src/Modules/Build.lua

@@ -596,24 +596,7 @@ function buildMode:Init(dbFileName, buildName, buildXML, convertBuild, importLin
 	--special rebuild to properly initialise boss placeholders
 	self.configTab:BuildModList()
 
-	-- Initialise class dropdown
-	for classId, class in pairs(self.latestTree.classes) do
-		local ascendancies = {}
-		-- Initialise ascendancy dropdown
-		for i = 0, #class.classes do
-			local ascendClass = class.classes[i]
-			t_insert(ascendancies, {
-				label = ascendClass.name,
-				ascendClassId = i,
-			})
-		end
-		t_insert(self.controls.classDrop.list, {
-			label = class.name,
-			classId = classId,
-			ascendancies = ascendancies,
-		})
-	end
-	table.sort(self.controls.classDrop.list, function(a, b) return a.label < b.label end)
+	self:UpdateClassDropdowns()
 
 	-- so we ran into problems with converted trees, trying to check passive tree routes and also consider thread jewels
 	-- but we can't check jewel info because items have not been loaded yet, and they come after passives in the xml.
@@ -1195,6 +1178,29 @@ function buildMode:OnFrame(inputEvents)
 	self:DrawControls(main.viewPort)
 end
 
+function buildMode:UpdateClassDropdowns(treeVersion)
+	local classes = main.tree[treeVersion or latestTreeVersion].classes
+	wipeTable(self.controls.classDrop.list)
+	-- Initialise class dropdown
+	for classId, class in pairs(classes) do
+		local ascendancies = {}
+		-- Initialise ascendancy dropdown
+		for i = 0, #class.classes do
+			local ascendClass = class.classes[i]
+			t_insert(ascendancies, {
+				label = ascendClass.name,
+				ascendClassId = i,
+			})
+		end
+		t_insert(self.controls.classDrop.list, {
+			label = class.name,
+			classId = classId,
+			ascendancies = ascendancies,
+		})
+	end
+	table.sort(self.controls.classDrop.list, function(a, b) return a.label < b.label end)
+end
+
 -- Opens the game version conversion popup
 function buildMode:OpenConversionPopup()
 	local controls = { }